No email is sent for user password reset

I am trying to reset a password for a user in our database, but the notification mail isn't sent to his email in order to login. I tried to reset many times since yesterday, but nothing. Could you please help me with that? Our project room is ilot.

I am trying to reset the password from the administrator--> user management tab and even though it says that the task has been successfully completed the email never reaches the user's inbox so as to follow the link and login.